What is the initial management of a patient presenting with hypotension?

Initial Management of Hypotension

The first priority in managing hypotension is urgent evaluation to identify and correct the underlying cause—whether hypovolemia, cardiogenic shock, vasodilatory shock, or other etiologies—followed by immediate restoration of adequate tissue perfusion through targeted fluid resuscitation and/or vasopressor support. 1

Immediate Assessment and Diagnosis

Exclude Reversible Causes First

• Rule out hypovolemia, vasovagal reactions, electrolyte disturbances, pharmacological side effects, and arrhythmias before diagnosing more complex shock states 1
• Hypotension in acute settings often suggests serious underlying pathology including cardiac arrhythmia, myocardial ischemia, aortic dissection, or shock 1
• Assess for specific clinical patterns to guide therapy:
  • Hypovolemia: venoconstriction, low jugular venous pressure, poor tissue perfusion 1
  • Cardiogenic shock: tachycardia, tachypnea, small pulse pressure, poor tissue perfusion, pulmonary edema 1
  • Bradycardia-hypotension: "warm hypotension," bradycardia, venodilatation, normal jugular venous pressure (often in inferior MI) 1
  • Right ventricular infarction: high jugular venous pressure, poor tissue perfusion, bradycardia, hypotension 1

Bedside Evaluation for Fluid Responsiveness

• Perform passive leg raise (PLR) test to predict fluid responsiveness before administering fluids 1
• An increase in cardiac output after PLR strongly predicts fluid responsiveness (positive likelihood ratio = 11; specificity 92%) 1
• No increase in cardiac output after PLR identifies patients unlikely to respond to fluid (negative likelihood ratio = 0.13; sensitivity 88%) 1
• Only ~50% of patients with suspected hypovolemia actually respond to fluid boluses, making assessment critical to avoid inappropriate fluid administration 1

Initial Fluid Resuscitation

Crystalloid Selection and Administration

• Initiate fluid therapy with 0.9% sodium chloride or balanced crystalloid solution as first-line treatment 1
• Avoid hypotonic solutions (such as Ringer's lactate in severe head trauma, or 5% dextrose which may exacerbate cerebral edema) 1
• Restrict colloid use due to adverse effects on hemostasis 1

Fluid Strategy Based on Clinical Context

• For hypovolemic patients: rapid replacement of depleted intravascular volume followed by maintenance IV fluids 1
• For euvolemic patients: initiate maintenance IV fluids at approximately 30 mL/kg/day 1
• In pediatric CRS-related hypotension: administer initial normal saline bolus (10-20 mL/kg; maximum 1,000 mL); if no improvement, initiate anti-IL-6 therapy 1
• Exercise caution in patients vulnerable to volume overload (renal failure, heart failure, cardiac dysfunction) 1

Permissive Hypotension in Trauma

• In hemorrhagic trauma, use restricted volume replacement with permissive hypotension (target systolic BP 80-90 mmHg) until bleeding is controlled 1
• Avoid vasopressors if target systolic BP of 80-90 mmHg can be achieved with fluids alone 1

Vasopressor and Inotropic Support

When to Initiate Vasopressors

• If restricted volume replacement fails to achieve target blood pressure, administer noradrenaline in addition to fluids 1
• In severe hypotension (systolic BP <80 mmHg) that fails to respond to fluids, transient noradrenaline is recommended to maintain life and tissue perfusion 1
• If arterial hypotension cannot be corrected rapidly by other means, use of vasopressor agents is reasonable 1

Specific Vasopressor and Inotrope Selection

Dopamine Dosing Algorithm 1, 2:

1. Begin at 2-5 mcg/kg/min for patients likely to respond to modest increments of heart force and renal perfusion 1, 2
2. In more seriously ill patients, start at 5 mcg/kg/min and increase gradually using 5-10 mcg/kg/min increments up to 20-50 mcg/kg/min as needed 1, 2
3. If signs of renal hypoperfusion are present, use dopamine 2.5-5.0 mcg/kg/min 1
4. More than 50% of patients are maintained on <20 mcg/kg/min 2
5. If doses >50 mcg/kg/min are required, check urine output frequently and consider dose reduction if urine flow decreases 2

Dobutamine 1:

• Preferred when pulmonary congestion is dominant 1
• Initial dosage 2.5 mcg/kg/min, increase gradually at 5-10 minute intervals up to 10 mcg/kg/min or until hemodynamic improvement 1
• Recommended for myocardial dysfunction 1

Noradrenaline 1:

• First-line vasopressor when fluid resuscitation fails to achieve target arterial pressure 1

Critical Monitoring During Vasopressor Use

• Infuse into large veins (antecubital fossa preferred) to prevent extravasation and tissue necrosis 2
• Use only an infusion pump, preferably volumetric, not gravity-based systems 2
• Monitor continuously: urine flow, cardiac output, blood pressure, peripheral perfusion 1, 2
• Reduce dosage if: diminished urine flow, increasing tachycardia, or new dysrhythmias develop 2

Context-Specific Management

Cardiogenic Shock

• Administer oxygen and loop diuretic 1
• Unless hypotensive, give IV nitroglycerin starting at 0.25 mcg/kg/min, increasing every 5 minutes until systolic BP falls to 90 mmHg 1
• Consider pulmonary artery catheterization to target wedge pressure <20 mmHg and cardiac index >2 L/min/m² 1
• Echocardiography is essential to assess myocardial damage, ventricular function, and mechanical complications 1

Acute Ischemic Stroke

• Urgent evaluation and correction of hypotension are critical to minimize brain damage 1
• The brain is especially vulnerable due to impaired cerebral autoregulation 1
• Hypotension on admission is associated with poor outcomes 1

Postoperative Hypotension

• Perform bedside assessment with PLR test to determine if preload, vascular tone, or inotropy correction is needed 1
• For positive PLR test, IV fluid is appropriate; if preload augmentation not needed, use vasopressor or inotropic support 1
• Phenylephrine is best used when hypotension is accompanied by tachycardia due to risk of reflex bradycardia 1

Critical Pitfalls to Avoid

• Do not add sodium bicarbonate or alkalinizing substances to dopamine, as it is inactivated in alkaline solution 2
• Avoid abrupt discontinuation of vasopressors; gradually decrease dose while expanding blood volume to prevent marked hypotension 2
• Exercise extreme caution with dopamine in patients receiving cyclopropane or halogenated hydrocarbon anesthetics due to risk of ventricular arrhythmias 2
• In patients on MAO inhibitors, use initial dopamine doses no greater than one-tenth the usual dose 2
• Do not rely on Trendelenburg positioning as primary treatment—evidence does not support significant improvement in blood pressure or cardiac output 3
• Recognize that sustained hypotension (systolic BP <100 mmHg for ≥60 minutes) is the strongest independent predictor of adverse hospital outcome (odds ratio 3.1) 4